TOP258PG Equivalent & Substitute Parts Reference

Part Overview

The TOP258PG is an offline switch flyback converter IC from Power Integrations' TOPSwitch®-HX series, designed for isolated power supply applications. This component operates at 66 kHz switching frequency with 48 W output power capability and integrated current limiting, over-temperature, and over-voltage protection. The TOP258PG is classified as obsolete; however, equivalent and substitute parts remain available in active production status, ensuring design continuity and supply chain reliability for existing applications requiring this topology and electrical specification set.

Key Parameters

Parameter	Value
Manufacturer	Power Integrations
Series	TOPSwitch®-HX
Topology	Flyback
Output Isolation	Isolated
Voltage - Breakdown	700V
Frequency - Switching	66 kHz
Duty Cycle	78%
Power (Watts)	48 W
Fault Protection	Current Limiting, Over Temperature, Over Voltage
Operating Temperature	-40°C ~ 150°C (TJ)
Package / Case	8-DIP (0.300", 7.62mm), 7 Leads
Mounting Type	Through Hole
RoHS Status	RoHS Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)
REACH Status	REACH Unaffected

Substitute Part Grouping Explanation

Substitution eligibility for the TOP258PG is determined by strict alignment of the following critical parameters:

Primary Substitution Criteria:

Manufacturer: Power Integrations
Series: TOPSwitch®-HX
Topology: Flyback
Output Isolation: Isolated
Voltage - Breakdown: 700V
Frequency - Switching: 66 kHz
Duty Cycle: 78%
Package / Case: 8-DIP (0.300", 7.62mm), 7 Leads
Mounting Type: Through Hole
Operating Temperature Range: -40°C ~ 150°C (TJ)
Fault Protection: Current Limiting, Over Temperature, Over Voltage
RoHS Status: RoHS Compliant
MSL: 1 (Unlimited)
REACH Status: REACH Unaffected

Secondary Variation Parameter:

Power (Watts): Varies across substitute parts (15 W to 48 W)

Substitute parts are grouped into two categories:

Category 1 - Direct Functional Equivalent (MFR Recommended): TOP258PN shares identical electrical specifications and fault protection features with the main part TOP258PG. The only difference is packaging format (Tube vs. standard). This part is in active production status.

Category 2 - Parametric Equivalents (Power Rating Variants): TOP252PG/PN, TOP253PG/PN, TOP254PG/PN, TOP255PN, TOP256PN, and TOP257PG maintain all critical electrical and mechanical parameters except power output rating. These parts operate at identical switching frequency, breakdown voltage, duty cycle, and protection features but deliver different maximum power levels (15 W to 41 W). Selection from this category requires application power requirement verification.

Parameter Comparison

Part Number	Manufacturer	Product Status	Power (W)	Voltage - Breakdown (V)	Frequency - Switching (kHz)	Duty Cycle (%)	Package	Operating Temp (°C)	Fault Protection	RoHS
TOP258PG	Power Integrations	Obsolete	48	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP258PN	Power Integrations	Active	48	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP252PG	Power Integrations	Active	15	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP252PN	Power Integrations	Active	15	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP253PG	Power Integrations	Active	25	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP253PN	Power Integrations	Active	25	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP254PG	Power Integrations	Active	28	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP254PN	Power Integrations	Active	28	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP255PN	Power Integrations	Active	30	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP256PN	Power Integrations	Active	34	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes
TOP257PG	Power Integrations	Active	41	700	66	78	8-DIP	-40 ~ 150	CL, OT, OV	Yes

Legend: CL = Current Limiting, OT = Over Temperature, OV = Over Voltage

Engineering Selection Recommendations

For Direct Replacement (Recommended Primary Path):

TOP258PN is the manufacturer-recommended substitute for TOP258PG. Both parts maintain identical electrical specifications, fault protection architecture, and thermal operating range. TOP258PN is in active production status with 25,300 units in stock, ensuring supply continuity. The only distinction is packaging format (Tube). This part is suitable for direct substitution in existing TOP258PG designs without circuit modification.

For Power-Scaled Applications:

When application power requirements differ from the original 48 W specification, the following active-status alternatives provide equivalent electrical topology and protection features at reduced power ratings:

TOP257PG: 41 W output (1,057 units available)
TOP256PN: 34 W output (19,116 units available)
TOP255PN: 30 W output (5,619 units available)
TOP254PG/PN: 28 W output (842 and 20,300 units available)
TOP253PG/PN: 25 W output (1,025 and 35,300 units available)
TOP252PG/PN: 15 W output (968 and 16,771 units available)

All substitute parts maintain 700V breakdown voltage, 66 kHz switching frequency, 78% duty cycle, and integrated current limiting, over-temperature, and over-voltage protection. Selection requires confirmation that application power demand does not exceed the chosen part's rated output.

Compliance Considerations:

All listed substitute parts carry RoHS Compliant status, MSL Level 1 (Unlimited moisture sensitivity), REACH Unaffected designation, and ECCN EAR99 classification, matching the original TOP258PG compliance profile.

Frequently Asked Questions (FAQ)

Q1: Can TOP258PN be used as a direct drop-in replacement for TOP258PG?

A: Yes. TOP258PN is the manufacturer-recommended equivalent. Both parts share identical electrical specifications, switching frequency (66 kHz), breakdown voltage (700V), duty cycle (78%), power rating (48 W), fault protection features, and 8-DIP through-hole package. The only difference is packaging format (Tube). No circuit modifications are required.

Q2: What is the difference between TOP258PG and TOP258PN?

A: The electrical and functional specifications are identical. TOP258PG uses standard packaging, while TOP258PN uses Tube packaging. TOP258PN is in active production status; TOP258PG is obsolete. For new designs or replacement stock, TOP258PN is the preferred selection.

Q3: Can I substitute a lower-power part like TOP256PN (34 W) for TOP258PG (48 W)?

A: Substitution is possible only if your application power requirement does not exceed 34 W. All electrical parameters (topology, switching frequency, breakdown voltage, duty cycle, protection features) remain identical. If your design requires the full 48 W capability, TOP256PN is not suitable. Verify actual power consumption before selecting a lower-rated part.

Q4: Can I substitute a higher-power part for a lower-power application?

A: Yes. Higher-power-rated parts from the TOPSwitch®-HX series (such as TOP258PN for applications originally designed for TOP252PG) maintain identical electrical topology and protection features. The higher power rating provides design margin. However, verify that the application circuit design accommodates the substitute part's specifications.

Q5: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute parts carry RoHS Compliant status, matching the original TOP258PG compliance requirement.

Q6: What is the difference between PG and PN packaging designations?

A: PG indicates standard packaging format; PN indicates Tube packaging. Both use the same 8-DIP (0.300", 7.62mm) through-hole package configuration. The designation reflects supplier packaging and handling format, not electrical or mechanical specifications.

Q7: Are there inventory differences between substitute parts?

A: Yes. Inventory levels vary significantly. TOP253PN has the highest availability (35,300 units), while TOP254PG has the lowest (842 units). For supply chain planning, verify current inventory status with your supplier before final part selection.

Q8: Do all substitute parts operate at the same switching frequency?

A: Yes. All listed substitute parts operate at 66 kHz switching frequency, maintaining design compatibility with transformer and filter component specifications.

Q9: What fault protection features are included in substitute parts?

A: All substitute parts include identical fault protection: current limiting, over-temperature protection, and over-voltage protection. These features are integral to the TOPSwitch®-HX architecture across all power ratings.

Q10: Can I use TOP252PG in a design originally specified for TOP258PG?

A: Only if your application power requirement is 15 W or less. TOP252PG maintains all electrical topology and protection features but is rated for 15 W maximum output. Exceeding this power rating may cause thermal stress and protection circuit activation. Confirm actual application power consumption before substitution.

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